Hot season triggers 100 bn tonnes Greenland ice loss

According to a latest finding, an unusually hot melting season in 2010 triggered ice loss of 100 billion tonnes in southern Greenland.

Large portions of the island’s bedrock rose an additional quarter of an inch. This is the finding from a network of nearly 50 GPS stations planted along the Greenland coast to measure the bedrock’s natural response to the diminishing weight of ice above it.

Every year as the Greenland Ice Sheet melts, the rocky coast rises, explained Michael Bevis, professor in the School of Earth Sciences at Ohio State University, who led the study.

Some GPS stations around Greenland routinely detect uplift of 15 mm (0.59 inches) or more, year after year. But a temperature spike in 2010 lifted the bedrock a detectably higher amount over a short five-month period — as high as 20 mm (0.79 inches) in some locations.

“The process is not really a steady process,” Bevis said, according to a university statement.

In scientific parlance, a melting day “anomaly” refers to the number of extra melting days — that is, days that were warm enough to melt ice — relative to the average number of melting days per year over several decades.

In 2010, the southern half of Greenland lost an extra 100 billion tons of ice under conditions that scientists would consider anomalously warm.

GNET measurements indicate that as that ice melted away, the bedrock beneath it rose.

The amount of uplift differed from station to station, depending on how close the station was to regions where ice loss was greatest.